CHEM 2261 Chapter : Chapter 1 Chem 2261

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azuremammoth471

15 Mar 2019

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Document Summary

H2 and he accounts for 99% mass of the universe. About 20 millions of known molecules, over 90% are organic. O2 is most abundant on earth, but carbon is uniquely suitable for life. The branch of chemistry focuses on studies of carbon- containing compounds. Protons and neutrons are about the same size- approx. Also composed of electrons (-)- negatively charged and much smaller than the other two 9. 1x10^-31 kg. Atomic number (z) = number of protons in nucleus (this must also equal the number of electrons in neutral atom) Mass number (a) = sum of number of protons. Each orbital is characterized by a unique set of quantum numbers. The principal quantum number n is a whole number (integer) that specifies the shell and is related to the energy of the orbital. The angular momentum quantum number is usually designated by a letter (s, p, d, f, etc) and describes the shape of the orbital.

Related Questions

Answer to the following short questions:

1. What is the percentage of chlorine present in ?

2. What is the volume in of of oil if its density is ?

3. Find the error(s) and rewrite the text in the correct form.

“According to the Dalton model for the atomic structure, the atomic structure is composed of a nucleus in the center and electrons orbiting around it. The Nucleus has always the same number of protons and neutrons and they are located in the Nucleus. The nucleus carries almost the whole of the mass of the atom. The nucleus is positively charged and the electron is negatively charged. Anions are obtained when electrons are lost. Anions and Cations form salts via ionic bonding. Salts are always soluble in water. All Covalent compounds (molecules) are not soluble in water”.

4. What is the oxidation number of the Sulphur atom in ?

5. The following equation describes the burning of hexane in oxygen: How many moles of water would be produced if of hexane was burnt in excess oxygen?